The image above is a rectangular prism.

To compute the area of a rectangular prism requires three essential parameters which are the length, width and height of the rectangular prism.

A = 2wl + 2hl + 2hw

Where;

A = Area of the rectangular prism

l = Length of the rectangular prism

w = Width of the rectangular prism

h = Height of the rectangular prism

Let’s solve an example;

Find the area of a rectangular prism with a width of 10 cm, a height of 17 cm and a length of 14 cm.

This implies that;

l = Length of the rectangular prism = 14 cm

w = Width of the rectangular prism = 10 cm

h = Height of the rectangular prism = 17 cm

A = 2wl + 2hl + 2hw

A = 2 x 10 x 14 + 2 x 17 x 14 + 2 x 17 x 10

A = 280 + 476 + 340

A = 1096

Therefore, the **area of the rectangular prism** is **1096 cm ^{2}.**

**Calculating the Length of a Rectangular Prism using the Area, Width and Height of the Rectangular Prism. **

l = ^{A – 2hw} / _{2 (w + h)}

Where;

l = Length of the rectangular prism

A = Area of the rectangular prism

w = Width of the rectangular prism

h = Height of the rectangular prism

Let’s solve an example;

Find the length of a rectangular prism with a width of 9 cm, a height of 12 cm and a Area of 250 cm^{2}.

This implies that;

w = Width of the rectangular prism = 9 cm

h = Height of the rectangular prism = 12 cm

A = Area of the rectangular prism = 250 cm^{2}

l = ^{A – 2hw} / _{2 (w + h)}

l = ^{250 – 2 x 12 x 9} / _{2 (9 + 12)}

l = ^{250 – 216} / _{2 (21)}

l = ^{34} / _{42}

l = 0.81

Therefore, the **length of the rectangular prism** is **0.81 cm.**

**Calculating the Width of a Rectangular Prism using the Area, Length and Height of the Rectangular Prism. **

w = ^{A – 2hl} / _{2 (l + h)}

Where;

l = Length of the rectangular prism

A = Area of the rectangular prism

w = Width of the rectangular prism

h = Height of the rectangular prism

Let’s solve an example;

Find the width of a rectangular prism with a length of 8 cm, a height of 11 cm and a Area of 340 cm^{2}.

This implies that;

l = Length of the rectangular prism = 8 cm

h = Height of the rectangular prism = 11 cm

A = Area of the rectangular prism = 340 cm^{2}

w = ^{A – 2hl} / _{2 (l + h)}

w = ^{340 – 2 x 11 x 8} / _{2 (8 + 11)}

w = ^{340 – 176} / _{2 (19)}

w = ^{164} / _{38}

w = 4.32

Therefore, the **width of the rectangular prism** is **4.32 cm.**

**Calculating the Height of a Rectangular Prism using the Area, Length and Width of the Rectangular Prism. **

h = ^{A – 2wl} / _{2 (l + w)}

Where;

l = Length of the rectangular prism

A = Area of the rectangular prism

w = Width of the rectangular prism

h = Height of the rectangular prism

Let’s solve an example;

Find the height of a rectangular prism with a width of 7 cm, a length of 13 cm and a Area of 400 cm^{2}.

This implies that;

l = Length of the rectangular prism = 13 cm

w = Width of the rectangular prism = 7 cm

A = Area of the rectangular prism = 400 cm^{2}

h = ^{A – 2wl} / _{2 (l + w)}

h = ^{400 – 2 x 7 x 13} / _{2 (13 + 7)}

h = ^{400 – 182} / _{2 (20)}

h = ^{218} / _{40}

h = 5.45

Therefore, the **height of the rectangular prism** is **5.45 cm.**

Nickzom Calculator – **The Calculator Encyclopedia** is capable of calculating the area of a rectangular prism.

To get the answer and workings of the area of a rectangular prism using the **Nickzom Calculator – The Calculator Encyclopedia. **First, you need to obtain the app.

You can get this app via any of these means:

**Web** – https://www.nickzom.org/calculator-plus

To get access to the **professional **version via web, you need to **register** and **subscribe **for** NGN 1,500 **per** annum** to have utter access to all functionalities.

You can also try the **demo **version via https://www.nickzom.org/calculator

**Android (Paid)** – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator

**Android (Free)** – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator

**Apple (Paid)** – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8

Once, you have obtained the calculator encyclopedia app, proceed to the **Calculator Map, **then click on **Mensuration**** **under the **Mathematics** section.

Now, click on** Area of a rectangular prism** under **Mensuration**

The screenshot below displays the page or activity to enter your values, to get the answer for the area of a rectangular prism according to the respective parameters which are the length, the width and the height of the rectangular prism.

Now, enter the values appropriately and accordingly for the parameters as required by the **example** above where the** width **is** 10 cm, the length** is** 14 cm and the height** is** 17 cm.**

Finally, Click on **Calculate**

As you can see from the screenshot above, **Nickzom Calculator** – The Calculator Encyclopedia solves for the** area of a rectangular prism** and presents the formula, workings and steps too.